Stabilization of motor fuels



Patented Nov. 6, 1951 STABILIZATION OF MOTOR FUELS Louis Schmerllng,

Riverside. and Joseph A.

Chenicek, Bensenville, !ll., assignors to Universal Oil ProductsCompany, Chicago, 111., a

corporation of Delaware No Drawing. Application February 8, 1949, SerialNo. 75,307

4 Claims. I

This invention relates to the stabilization of motor fuels which tendsto deteriorate in storage due to oxidation reactions. It is an object ofthe present invention to prevent or at least substantially retard theundesirable deterioration of motor fuels comprising olefinic gasolinessuch as cracked gasoline and polymer gasoline.

In a broad embodiment, the present invention relates to a method ofstabilizing motor fuels which comprises incorporating therein aninhibitor comprising a hydroxyphenylpiperidine.

In, a specific embodiment, the present invention relates to a method ofstabilizing cracked gasoline which comprises incorporating therein fromabout 0.0001% to about 0.1% by weight of 1- (p-hydroxyphenyl) -4,4-dimethylpiperidine.

The preferred inhibitor of the present invention compriseshydroxyphenyl-piperidines and particularly 1-(p-hydroxyphenyl)4,4-dimethylpiperidine which is illustrated in the following formula.

.These compounds may readily be prepared by the reaction of a 1,5-dihaloalkane with paminophenol or by the reaction of hydroquinone witha piperidine. The reaction is readily effected by refluxing thereactants at a suitable temperature which may range from about 50 toabout 200 C. and preferably is of the order of 75 to 125 C. A suitablesolvent such as dioxane may be utilized in the preparation of thecompound, and the dioxane may be distilled off and the residuumextracted with a suitable solvent and recovered by recrystallization.

Referring to the structural formula hereinbefore set forth, it isunderstood that the aromatic ring and/or the heterocyclic ring maycontain various further substituents including alkyl, aryl, aralkyl,alkaryl, alkoxy, aralkoxy, hydroxy, etc., radicals and that thesealternative, but not necessarily equivalent, compounds may be preparedby further alkylating the above compound or by the use of other startingmaterials P The inhibitor of the present invention will usually be addedto gasoline in an amount of less than 0.5% by weight and generally willbe utilized in an amount of from about 0.0001% to about 0.1%. The exactamount of inhibitor required will depend upon the particular motor fuelbeing treated and upon the stability desired. These inhibitors may alsobe employed in connectiun with various dyes, antiknock agents such astetraethyl lead, metal deactivators or other additives employed forspecific purposes in the motor fuel.

The following example is introduced to illustrate further the noveltyand utility of the present invention but not with the intention ofunduly limiting the same.

1 (p-hydroxyphenyl) 4,4 dimethylpiperidine was prepared as follows: Asolution of 11 g. of p-aminophenol and 13 g. of 1,5-dibr0mo-3,3-dimethyl pentane in 53 g. of dioxane was refluxed at 103 C. for 12hours. The dioxane was distilled off and the residue was extracted withether and recrystallized from alcohol to recover the desired compoundhaving a melting point of 129-130 C.

The above compound was tested as an inhibitor in cracked gasoline whichhad a blank induction period of minutes. 0.005% of the compound preparedin the above manner was added to the cracked gasoline. The inductionperiod of the cracked gasoline was increased from 45 minutes to 365minutes upon the addition of the inhibitor. The induction period isdetermined by the Oxygen Bomb Stability Test which is a standard methodfor evaluating the storage stability of gasoline.

We claim as our invention:

'1. Oleflnic gasoline containing a small amount of al-hydroxyphenyl-piperidine, sufficient to retard oxidative deteriorationof the gasoline.

2. Cracked gasoline containing a small amount of 1- (p-hydroxyphenyl)-4,4-dimethylpiperidine, sumcient to retard oxidative deterioration ofthe gasoline.

3. Cracked gasoline containing from about 0.0001% to about 0.1% byweight of l-(p-hydroxyphenyl) -4,4-dimethylpiperidine.

4. Olefinic gasoline containing a small amount of al-(p-hydroxyphenyl)-piperidine, sufficient to retard oxidativedeterioration of the gasoline.

LOUIS SCHMERLING. JOSEPH A. CHENICEK.

REFERENCES CITED UNITED STATES PATENTS Name Date Chenicek et a1. Oct.17, 1942 Number

1. ALEFINIC GASOLINE CONTAINING A SMALL AMOUNT OF A1-HYDROXYPHENYL-PIPERIDINE, SUFFICIENT TO RETARD OXIDATIVE DETERIORATIONOF THE GASOLINE.